Recent wireless communication environments are faced with the problem of a rapid increase in data traffic. Thus, IEEE 802.11 that is one of the standards related to wireless local area network (LAN) employs technology such as multi-user multiple-input multiple-output (MU-MIMO) as disclosed in Non-Patent Literature 1 below to achieve high-speed wireless communication environment.
In the wireless LAN system, a scheme called carrier sense multiple access with collision avoidance (CSMA/CA) is spreading as one of techniques for avoiding collision. CSMA/CA is a process of checking that another wireless terminal is not transmitting on the frequency channel to be used. A wireless terminal performs wireless transmission when another terminal is not transmitting, and is prevented from performing wireless transmission when the other terminal is transmitting.